In the ancient Mesopotamian and Indus Valley cultures, a small, cylindrical stone incised with a figural scene, design, and/or inscription. When the seal was rolled across wax or wet clay, the resulting raised image served as a mark of ownership or an authenticating signature. Web resource here.
Cylinder seal. Mesopotamian. Ca. 2350-2150 BCE. University of Pennsylvania Museum of Archaeology and Anthropology, Philadelphia.